CODEWITHSUNDEEP
c++
spaghetticode
spaghetticode

Reputation: 35

How to keep taking values from the user in C but stop when the user does not enter any value and presses enter?

int k;
vector<int>v;
while ((scanf("%d", &k)) != EOF) {
    if (v.size() > 20) break;
    else {
        if (k > 0 && k <= 120) v.push_back(k);
    }
}

**The above snippet is taken from codechef blogs **

Upvotes: 1

Views: 52

Answers (1)

Serge Ballesta
Serge Ballesta

Reputation: 149185

<rant>Never tag a question both C and C++ on SO again. It is reserved for questions about interoperations or very specific language-lawyer points, and should not be used for code that could be more or less used on both languages. In that latter case choose one in your first question and if you later need it ask a new question for the other language</rant>

Your problem is that for the scanf family questions spaces and newlines are just ignored when you use a %d conversion character. And scanf returns the number of elements that could be decoded and only stops on an end of file, read error or conversion error.

If you want to be able to detect an empty input, you will have to use fgets + sscanf from the C standard library, or getline + stringstream from the C++ one.

Upvotes: 3

Related Questions